Cooling and handling of petroleum pitches



Aug. 13, 1957 M. E. NASH 2,802,235

COOLING AND HANDLING OF PETROLEUM PITCHES Filed July 27, 1953 2 Sheets-Sheet 1 3' INVENTOR.

- M.ENASH Mk/y ATTORNEYS 1957 M. E. NASH 2,802,236

COOLING AND HANDLING OF PETROLEUM PITCHES Filed July 27, 1953 2 Sheets-Sheet 2 INVENTOR. M.E.NASH

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ATTORNEYS COOLING AND HANDLING OF PETROLEUM PITCI-IES Application July 27, 1953, Serial No. 37 0,573

16 Claims. (Cl. 18-1) This invention relates to the cooling of liquids so as to form solid products flaky and granular in structure. In one of its specific aspects, it relates to the cooling of hot liquid petroleum pitch. In another of its specific aspects, it relates to a process for cooling hot liquid petroleum pitch and recovering solid pitch, flaky and granular in form.

It has recently been found that petroleum pitches having properties equal or superior to those of coal tar pitch can be produced from certain pre-selected feedstocks by a vacuum distillation process. Because of their superior properties, these pitches have found numerous industrial uses, such as in the making of coal briquettes, the manufacture of electrodes for aluminum refining, and the fabrication of certain types of pressed board products. For a detailed description of such petroleum 1 pitches and a process for their production, reference may be had to my copending U. S. application, Serial No. 328,989, filed December 31, 1952, now Patent No. 2,768,119.

In the production of petroleum pitches, one of the many problems encountered has been that of providing a practical, efiicient, and reasonably rapid method of cooling the hot liquid product. Closely associated with the problem of cooling are those of handling and storage, for it is desirable to obtain a solid pitch product, flaky and granular in form in order to promote ease of handling, storage and shipment. Since pitch becomes an excellent insulator after solidification, only small thicknesses can be rapidly cooled to form a solid product. Because of this poor thermal conductivity of pitch, it is estimated that about two years would be required to solidify a pond of liquid pitch about 20 feet deep, or still again about a five-day cooling period would be required to solidify pitch in pans or enclosures about one foot thick. If the pitch is thus allowed to cool naturally, it is apparent that a vast area would have to be set aside for the cooling operation in order to accommodate even a small volume of production. And furthermore, in order to recover an uncontaminated pitch product, an enclosed installation would be called for if a method of natural cooling of the pitch is utilized. In addition to the expensive installation involved, there is the further objection to natural cooling in that the product obtained is not of the desired flaky granular form.

There are several other cooling methods available which can be employed, but which have certain disadvantages. One of these methods involves rotating a cooled (1111111 in a pan of liquid pitch so as to form thereon a thin film of solid pitch which is shaved from the drum as it rotates. Another somewhat similar method utilizes an endless belt mounted on a pair of pulleys, the lower portion of the belt being submerged in a pan of liquid pitch. As the belt passes through the liquid, it picks up a thin film of pitch which is subsequently cooled and removed from the belt as it passes over one of the pulleys.. It is evident that the rotating drum or endless belt. type. methods of cooling would involve extremely nited States Patent ice large installations which would materially increase the production costs of solid pitch. Still again liquid 'petroleum pitch can be cooled by water contacting methods, such as sluicing and prilling in a water fogging tower. Such latter methods, however, result in an undesirable product containing occluded and absorbed water. By employing the cooling process of this invention the disadvantages of the above enumerated methods are eliminated, and it is possible to obtain an uncontaminated solid pitch product, flaky and granular in structure.

The objects and advantages of the present invention will be attained by the various aspects of the invention.

It is an object of this invention to provide. a method of cooling liquids so as to form solid products, flaky and granular in structure.

Another object is to provide a method for cooling hot liquid petroleum pitch.

A further object is to provide a method for cooling hot liquid petroleum pitch so as to obtain a solid pitch product, flaky and granular in structure.

Still other objects and advantages will become apparent to one skilled in the art from a consideration of the accompanying disclosure.

Broadly, the present invention involves the cooling of solid spheres to a temperature below the melting point of the petroleum pitch and the coating of the cooled spheres with hot liquid petroleum pitch so as to form thereon a thin film of solid pitch. Thereafter, the coated spheres are continuously agitated so as to remove the thin film of solid pitch which is recovered in flaky granular form.

For a more complete understanding of the invention, reference may be had to the drawing in which:

Figure l is a diagrammatic elevational view, partly in section, of one arrangement of apparatus suitable for practicing the invention, and

Figure 2 is a diagrammatic elevational view, partly in section, of another arrangement of apparatus suitable for practicing the invention.

Referring to Figure l of the drawing, a substantially vertically disposed shell 11 is closed at its upper end b'y closure member 1-2. and at its lower end by closure member 13. Closure member 13 is preferably funnel shaped in order to facilitate removal of solid heat transfer material from the bottom of shell 11. Shell 11 is divided into an upper or cooling chamber 14 and a lower or liquid contact chamber 16 by means of inverted conical member 17 which is attached to the walls of the shell. Cooling chamber 14 is provided with a solid heat transfer material inlet conduit 18 while contact chamber 16 has an outlet conduit 19. The two chambers are connected by throat 21 attached to conical member 17 and containing a fiow control means such as star valve 22, a gate valve or the like. Outlet conduit 19 is provided with a similar flow control means 23. It is also within the contemplation of the invention to omit star valve 22 from throat 21 and effect the desired control solely by means of flow control means 23. A fluid inlet means 24 communicates with the lower part of chamber 14 while fluid outlet means 26 is positioned in closure member 12. The apparatus include liquid inlet means 27 connected to liquid distributor ring 28 having perforations 29 therein for the distribution of the hot liquid petroleum pitch. Distributor ring 28 is positioned within chamber 16 above the bed of heat transfer material so.

that the material will pass through the ring on leaving throat 21. The perforations are spaced along the inside circumference of the ring and are also staggered along the under part of the ring.

Positioned below outlet conduit 19 is a means 31 for agitating and abrading the heat transfer material, which agitating means in turn is disposed within hopper 32,

Agitating means 31 comprises a container 33 having sides and bottom formed of wire screening of a mesh small enough to prevent the escape of heat transfer material while at the same time allowing the particulate solid pitch to pass therethrough. Outlet conduit 19 communicates with the interior of container 33 through an opening in plate 34 which covers the top of the container. Vertical shaft 36, operatively connected to motor 37, is disposed within container 33 and attached to the shaft are horizontal arms or rods 38 which are illustrated as being of varying lengths. The distance between the ends of any arm and the walls of the container should be greater than the diameter of the heat transfer material and preferably not less than about two or three diameters. A horizontal arcuate member 39, which is attached to the shaft in close proximity to the bottom of container 33, is disposed so that its leading edge is convex.

"Outlet conduit 41 leads from container 33 into the lower part of elevator 42. That part of conduit 41 which is positioned within hopper 32 has a bottom portion 40 constructed of wire screening similar to that used with container 33. Elevator 42 is illustrated as being a conventional gas lift elevator provided with a gas inlet 43 and a gas outlet 44. Conduit 45 connects the upper part of elevator 42 with inletconduit 18.

' Referring to Figure 2, which illustrates another arrangement of apparatus for practicing the invention, a substantially vertically disposed shell 51 is closed at its upper end by closure member 52 and at its lower end by closure member 53 so as to form therein liquid contact chamber 54. Closure member 53 is preferably funnel shaped and is provided with an outlet conduit 56 containing a fiow control means 57 such as a star valve. Liquid inlet means 58 is connected to liquid distributor ring 59 having perforations therein for the distribution of the hot liquid petroleum pitch. Distributor ring 59 is disposed within the upper part of chamber 54 so that the heat transfer material on entering the chamber will pass through the ring. A substantially horizontal shaft 62 operatively connected to motor 63 extends through the side of shell 51 and is supported within liquid contact chamber 54 by means of bearings 64 and 66. Stirrer rods 67 atfixed to shaft 62 at spaced intervals along its length provide means for continuously stirring the solid heat transfer material within the liquid contact chamber. While the stirring means is illustrated as comprising a single horizontal shaft with attached rods, it is Within the scope of the invention to utilize more than one shaft or to dispose the shaft or shafts in other positions as, for example, vertically. Furthermore, the stirring means is not restricted to the apparatus of Figure 2, but can be used in conjunction with the apparatus of Figure 1. Agitating means 31 and gas lift elevator 42 are similar to those described in conjunction with Figure 1, and identical numerals have been used to indicate corresponding elements.

In the operation of the apparatus of Figure 1, solid heat transfer material is introduced into cooling chamber 14 through inlet conduit 18 and takes the form of a contiguous mass or bed having an upper surface 15. Solid spheres having a diameter from about /a inch to about inch are utilized as the heat transfer material. While it is preferred that the spheres be formed of a metal such as steel or aluminum, it i within the scope of the invention to employ spheres formed of ceramic material such as are utilized in conjunction with pebble heater apparatus. A liquid refrigerant such as propane is introduced into the lower part of cooling chamber 14 through fluid inlet means 24 in commingled relation with the solid spheres. The liquid refrigerant evaporates lowering the temperature of the spheres to a point substantially below the softening point of the petroleum pitch.

The cooled solid spheres flow downwardly through throat 21 into liquid contact chamber 16 as a contiguous mass to form a bed therein having an upper surface 20. The rate of flow of the solid spheres into chamber 16 can all) be controlled by means of star valve 22, or alternatively star valve 22 can be omitted and the desired rate of fiow obtained by regulating star valve 23 in outlet conduit 19. Hot liquid petroleum pitch is passed into chamber 16 through liquid inlet means 27 which is connected to distributor ring 28. Perforations 29 in distributor ring 28 are so located that the pitch leaves the distributor ring in a plurality of streams, which impinge against the spheres as they pass across surface 20. By distributing the hot liquid pitch in this manner, the cool solid spheres are coated with a thin film of liquid pitch which upon contact immediately solidifies to form solid pitch. The thickness of this film is preferably about A to A inch, although some of the solids may be coated with films of greater or less thickness, depending upon the'size and nature of the solids. The coated spheres thereafter gravitate downwardly through chamber 16 and pass through outlet conduit 19 into container 33. The rate of flow of the spheres into container 33 can be controlled by star valve 23. When the spheres enter container 33, they are struck by arms 38 which are slowly rotating with shaft 36. The impact of the spheres against the sides of container 33 and against one another causes the coating of solid pitch to crack and break off from the spheres. Because of the brittleness of the thin film, only a comparatively small amount of agitation of the spheres by slow rotation of the arms is necessary in order to completely clean the spheres. Most of the flaky granular pitch falls to the bottom of container 33 and passes through the screen to hopper 32 while some passes through the side screens into the hopper. Arcuate member 39, which turns with shaft 36 and is positioned in close proximity to the bottom screen, wipes the bottom of container 33 clean and breaks up or forces any of the larger pieces of solid pitch through the screen. The spheres leave the container through the conduit 41 which is partly screened to take care of any of the pitch which might pass into the conduit with the spheres. Arcuate member 39 also propels any of the spheres which may tend to settle in the bottom of container 33 into conduit 41. The spheres enter the bottom of gas lift elevator 42 through conduit 41 and are lifted by means of air introduced through line 43 to the top of the elevator. Thereafter, the spheres leave the elevator through conduit 45 which connects with inlet conduit 18 through which the spheres pass into cooling chamber 14.

It is also Within the scope of the invention, utilizing the apparatus of Figure 1, to use a stream of cold air to cool the spheres within chamber 14. In this embodiment of the invention the spheres are sprayed with water as they pass through conduit 45. The water is sprayed upon the spheres by nozzle 47 connected to water line 46. Excess water is removed from conduit 45 through screening 48 disposed in the bottom of conduit 45 and surrounded by container 49 having an outlet line 50 connected thereto. A stream of cold air which is passed into chamber 14 through line 24 dries and cools the downwardly moving mass of moist spheres. The air and moisture leave the chamber through outlet means 26, and thereafter the operation of the apparatus proceeds as explained in conjunction with Figure 1. Outlet 26 may be connected to means, not shown, for producing a partial vacuum above upper surface 15 of the bed of solid heat transfer material.

In the operation of the apparatus of Figure 2, a stream of cold air is introduced into gas lift elevator 42 through line 43. The spheres are cooled in their passage through the elevator by contact with the cold air and are then introduced into chamber 54 through inlet conduit 18 connected to elevator 42 by conduit 45. The cool spheres are contacted with hot liquid petroleum pitch so as to form thereon a thin film of solid pitch as previously described. The coated spheres thereafter gravitate downwardly through chamber 54 and pass through outlet conduit 56, provided with valve 57 for flow control, into container 33. The operation of the apparatus of Figure 2 then proceeds :as described in conjunction with Figure 1.

In the operation of the apparatuses of Figures 1 and 2, the spheres after being coated with the liquid pitch may tend to agglomerate. In order to guard against possible agglomeration and resultant bridging which would impede the flow of :spheres into and through outlet conduits 19 and 56, stirring means can be provided within liquid contact chambers 16 and 54. ,As illustrated in Figure 2, shaft 62 with attached rods 67 is slowly and continuously rotated, thereby preventing the spheres from cementing together and allowing free passage of the spheres through the chamber.

While the present invention has been described specifically in relation to the cooling of hot liquid petroleum pitch, it is within the contemplation of the invention to cool other pitches, such as coal tar pitch, and other liquids so as to form solid products, flaky and granular in structure. Examples of liquids which can be cooled utilizing the process of this invention are liquid sulphur, liquid caustic soda, liquid sodium sulphide and liquid waxes.

As will be evident to those skilled in the art, various modifications of this invention can be made or followed is the light of the foregoing disclosure and discussion without departing from the spirit or scope of the invention.

I'claim:

l. A process for forming granular solid products from hot liquid products which comprises coating a cooledmass of solid fragmentary heat transfer material with a hot liquid product; agitating said solid heat transfer material so as to remove therefrom the coating of solid product in granular form; and separating said solid heat transfer material from said solid product.

2. A process for forming granular petroleum pitch which comprises coating a cooled mass of solid fragmentary heat transfer material with hot liquid petroleum pitch; agitating said solid heat transfer material so as to remove therefrom the coating of solid pitch in granular form; and separating said solid heat transfer material from said solid pitch.

3. A process for forming granular petroleum pitch which comprises cooling a mass of solid fragmentary heat transfer material; thereafter spraying said solid heat transfer material with hot liquid petroleum pitch so as to form thereon a thin film of solid pitch; agitating said solid heat transfer material so as to remove therefrom said film of solid pitch in granular form; and separating said solid heat transfer material from said solid pitch.

4. A process for forming granular petroleum pitch which comprises introducing cooled solid spheres into the top of a vertically elongated chamber; contacting said spheres with a spray of hot liquid pitch; removing the spheres coated with a thin film of solid pitch from the bottom of said chamber; agitating said spheres so as to remove therefrom said thin film of pitch in granular form; separating the clean spheres from the solid pitch; passing the clean spheres into a gas lift elevator; and elevating said spheres to the top of said chamber by means of a cold stream of air, thereby cooling said spheres.

5. The process of claim 4 wherein the spheres after being contacted with hot liquid pitch are continuously and slowly stirred within said chamber so as to prevent agglomeration of the coated spheres.

6. A process for forming granular petroleum pitch which comprises introducing moist solid spheres into the upper portion of a vertically elongated cooling chamber; passing a stream of cold air into the lower part of said cooling chamber in commingled relation with said solid spheres, thereby drying and cooling same; withdrawing the air and moisture from the upper portion of said cooling chamber; gravitating the cooled solid spheres from the lower portion of said cooling chamber into a liquid contact chamber; contacting said cooled spheres with a spray of hot liquid petroleum pitch; removing the spheres coated tion of said cooling chamber.

7. The process of claim 6 wherein the spheres after being contacted with hot liquid pitch are continuously and slowly stirred within said liquid contact chamber so as to prevent agglomeration of the coated spheres.

8. A process for forming granular petroleum pitch which comprises introducing solid spheres into the upper portion of a vertically elongated cooling chamber; passing a liquid refrigerant into the lower part of said cool ing chamber in commingled relation with said solid spheres; evaporating said liquid refrigerant, thereby cooling said solid spheres; removing the vaporized refrigerant from the upper portion of said cooling chamber; gravitating the cooled solid spheres from the lower portion of said cooling chamber into a liquid contact chamber; contacting said cooled spheres with a spray of hot liquid petroleum pitch; removing the spheres coated with a thin film .of solid pitch from the lower portion of said liquid contact chamber; agitating the spheres so as to remove therefrom said thin film ofsolid pitch in granular form;

. separating the clean spheres from the solid pitch; and

returning the spheres to the upper portion of ing chamber.

9,. The process of claim .8 wherein the spheres after being contacted with hot liquid pitch are continuously and slowly stirred within said liquid contact chamber so as to prevent agglomeration of the coated spheres.

10. A process for forming granular petroleum pitch which comprises introducing solid spheres into a cooling zone; cooling said spheres to a temperature substantially below the softening point of liquid petroleum pitch; gravitating the cooled spheres into a liquid contact zone; contacting said cooled spheres with a spray of hot liquid petroleum pitch so as to form thereon a thin film of solid pitch; removing the coated spheres from said contact zone; agitating said spheres so as to remove therefrom said thin film of solid pitch in granular form; separating the clean spheres from the solid pitch; and returning said clean spheres to said. cooling zone.

11. Apparatus for forming solid granular products from liquids which comprises, in combination, a substantially vertically-disposed, closed shell; a liquid distribution means in the chamber formed within said shell; solid material inlet means in the upper portion of said chamber; solid material outlet means in the lower portion of said shell; means for agitating solid material disposed below said outlet means; and gas-lift means for elevating solid material from said agitating means to said solid material inlet means.

.12. Apparatus for forming solid granular products from liquids which comprises, in combination, a substan tially vertically-disposed, closed shell; a liquid distribution means in the chamber formed within said shell; means for stirring solid material within said chamber; solid material inlet means in the upper portion of said shell; solid material outlet means in the lower portion of said shell; means for agitating solid material disposed below said outlet means; and gas-lift means for elevating solid material from said agitating means to said solid material inlet means.

13. Apparatus for forming solid granular products from liquids which comprises, in combination, a substantially vertically-disposed, closed shell; an inverted conical member attached to the walls of said shell intermediate its ends, thereby forming an upper and a lower chamber within said shell; solid material conduit means attached to said conical member and communicating said upper chamber with said lower chamber; solid material inlet means in the upper part of said shell; fluid outlet means in the upper part of said shell; fluid inlet means in comsaid coolmunication with the lower portion of said upper chamber; liquid distribution means inthe upper portion of said lower chamber; solid material outlet means in the lower part of said shell; means for agitating solid material disposed below said solid material outlet means; and gaslift means for elevating solid material from said agitating means to said solid material inlet means.

14. Apparatus for forming solid granular products from liquids which comprises, in combination, a substantially vertically-disposed, closed shell; an inverted conical member attached to the walls of said shell intermediate its ends, thereby forming an upper and a lower chamber within said shell; solid material conduit means attached to said conical member and communicating said upper chamber with said lower chamber; solid material inlet means in the upper part of said shell; fluid outlet means in the upper part of said shell; fluid inlet means in communication with the lower portion of said upper chamber; liquid distribution means in the upper portion of said lower chamber; means for stirring solid material within said lower chamber; solid material outlet means in the lower part of said shell; means for agitating solid material disposed below said solid material outlet means; and gas lift means for elevating solid material from said agitating means to said solid material inlet means.

15. Apparatus for forming solid granular products from liquids which comprises, in combination, a substantially vertically-disposed, closed shell; an inverted conical member attached to the walls of said shell intermediate its ends,thereby forming an upper and a lower chamber within said shell; solid material conduit means attached to said conical member and communicating said upper chamber with said lower chamber; solid material inlet means in the upper part of said shell; fluid outlet means in the upper part of said shell; fluid inlet means in communication with the lower portion of said upper chamber; liquid distribution means in the upper portion of said lower chamber; solid material outlet means in the lower part of said shell; means for agitating solid material disposed below said solid material outlet means; gas-lift means for elevating solid material, said means having its lower end connected to said agitating means; a solid material conduit connected between the upper end of said gas-lift means and said solid material inlet means; and means for spraying solid material with water disposed in said solid material conduit.

16. The apparatus of claim 15 in which a means for stirring solid material is disposed within said lower chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,698,345 Puening Jan. 8, 1929 1,807,223 Miller May 26, 1931 2,494,695 Fisher Jan. 17, 1950 2,609,332 Bowles et al. Sept. 2, 1952 

1. A PROCESS FOR FORMING GRANULAR SOLID PRODUCTS FROM HOT LIQUID PRODUCTS WHICH COMPRISES COATING A COOLED MASS OF SOLID FRAGMENTARY HEAT TRANSFER MATERIAL WITH A HOT LIQUID PRODUCT; AGITATING SAID SOLID HEAT TRANSFER MATERIAL SO AS TO REMOVE THEREFROM THE COATING OF SOLID PRODUCT IN GRANULAR FORM; AND SEPARATING SAID HEAT TRANSFER MATERIAL FROM SAID PRODUCT. 